Morphological changes in the femoral and tibial bone tunnels after anatomic single-bundle anterior cruciate ligament reconstruction using a calcium phosphate-hybridized tendon graft in 2years of follow-up

Computational modelling of the graft-tunnel interaction in single-bundle ACL reconstructed knee

OBJECTIVES

Tunnel enlargement and graft failure are common complications associated with ACL reconstruction. The mechanical interaction between the graft and the tunnel aperture may play a more important role. This study aims to evaluate graft position within femoral tunnel and the graft force under external loads.

METHODS

An FE model of the femur-graft-tibia complex was constructed from CT images of an anatomically reconstructed knee specimen. The model was subjected to kinematics of passive flexion extension, anterior/posterior translation, internal/external rotation and valgus kinematics, which were collected from experimental testing. Graft shift and rotation of graft-tunnel contact region during flexion/extension and external loadings were recorded and compared to experimental measurements.

RESULTS

Model showed that the graft shifted in the femoral tunnel during flexion and under external loads. The graft-tunnel contact area rotated by up to 55° during flexion from full extension to 90° of extension implying that the so-called "wiper effect" occurs during most of flexion angles.

CONCLUSIONS

Different regions of the femoral tunnel aperture, particularly the anterior region, were under significantly more contact force from the graft than other areas of the aperture during the anterior translation test, potentially leading to femoral tunnel enlargement to the anterior side of the aperture.

Anatomical Single-Bundle Anterior Cruciate Ligament Reconstruction Using a Calcium Phosphate-Hybridized Tendon Graft with More than an Average of 5 Years of Follow-Up: A Follow-Up Study of a Randomized Controlled Trial

Calcium phosphate (CaP)-hybridized tendon grafting using an alternate soaking process improves tendon-to-bone healing in anterior cruciate ligament (ACL) reconstructions. This study aimed to compare bone tunnel enlargement, knee osteoarthritis, and clinical results between CaP-hybridized tendon grafting and conventional grafting in anatomical single-bundle ACL reconstruction. This study was a follow-up of a randomized controlled trial. Between July 2011 and December 2015, 90 patients underwent unilateral anatomical single-bundle ACL reconstructions and were randomly assigned to the CaP-hybridized tendon grafting (CaP group, n = 45; age, 27.1 [14-54] years; sex, 21 males and 24 females) or conventional grafting (control group, n = 45; age, 22.9 [13-58] years; sex, 26 males and 19 females). The randomization was performed according to the days of the week when the patients first visited the outpatient. The CaP-hybridized tendon grafting was created intraoperatively. The tendon grafts were soaked in a calcium solution for 30 s. After that, the tendon grafts were soaked in a NaHPO4 solution for 30 s. This soaking cycle between the calcium solution and the NaHPO4 solution was repeated 10 times. The bone tunnel enlargement, osteoarthritis grade, clinical score, and sports level were evaluated in patients who could be followed up for >3 years (CaP group, n = 20, average follow-up period 6.0 [5.1-6.9] years; control group, n = 15, average follow-up period 5.6 [4.3-6.9] years). Clinical scores, sports levels, and osteoarthritis grades were analyzed using a generalized linear mixed model (GLMM) based on repeated measurement data from preoperative and final observations, with time, group, sex, age, and BMI as fixed effects and the effect of individual differences as variable effects. In addition, bone-tunnel enlargements were analyzed using generalized linear models (GLM) with group, sex, age, and BMI as the main effects. Compared with the control group, the CaP group exhibited significantly reduced bone-tunnel enlargement on the femoral side (anteroposterior diameter; CaP group, 7.9% [-1.1-16.8] vs. control group, 29.2% [17.9-40.5], p = 0.004, MCID 16.05, proximal-distal diameter; CaP group, 7.9% [-1.9-17.8] vs. control group, 22.8% [10.9-34.7], p = 0.062, MCID 15.00). The osteoarthritis grades progressed in both groups (p < 0.001). The clinical scores and sports levels were not significantly different between the groups. This study suggests that the calcium phosphate-hybridized tendon graft reduces femoral bone-tunnel enlargement after anatomical single-bundle anterior cruciate ligament reconstruction in an average >5-year follow-up period. A longer follow-up period is necessary to reveal the clinical effects of the calcium phosphate-hybridized tendon grafts in anterior cruciate ligament reconstruction.

ACL graft with extra-cortical fixation rotates around the femoral tunnel aperture during knee flexion

PURPOSE

An understanding of the behavior of a new ACL graft in the femoral tunnel during knee motion and external loading can provide information pertinent to graft healing, tunnel enlargement, and graft failure. The purpose of the study was to measure the percentage of the tunnel filled by the graft and determine the amount and location of the graft-tunnel contact with knee motion and under external knee loads.

METHODS

Single bundle anatomical ACL reconstruction was performed on six cadaveric knees. Specimens were positioned with a robotic testing system under: (1) passive flexion-extension, (2) 89-N anterior and posterior tibial loads, (3) 5-N m internal and external torques, and (4) 7-N m valgus moment. The knees were then dissected, repositioned by the robot and the geometry of the femoral tunnel and graft were digitized by laser scanning. The percentage of tunnel filled and the contact region between graft and tunnel at the femoral tunnel aperture were calculated.

RESULTS

The graft occupies approximately 70% of the femoral tunnel aperture and anterior tibial loading tended to reduce this value. The graft contacted about 60% of the tunnel circumference and the location of the graft-tunnel contact changed significantly with knee flexion.

CONCLUSION

This study found that the graft tends to rotate around the tunnel circumference during knee flexion-extension and contract under knee loading. The "windshield-wiper" and "bungee cord" effect may contribute to femoral tunnel enlargement, affect graft healing, and lead to graft failure. There can be a considerable motion of the graft in the tunnel after surgery and appropriate rehabilitation time should be allowed for graft-tunnel healing to occur. To reduce graft motion, consideration should be given to interference screw fixation or a graft with bone blocks, which may allow an earlier return to activity.

Effects of Platelet-Rich Plasma on Tendon-Bone Healing After Anterior Cruciate Ligament Reconstruction

OBJECTIVE

To investigate the effect of platelet-rich plasma on tendon-bone healing after anterior cruciate ligament reconstruction.

METHODS

This retrospective study included 85 patients (range, 18-50 years; mean age, 33.95 ± 10.53 years; male/female, 49/36) who underwent anterior cruciate ligament reconstruction using autologous hamstring tendons between August 2017 and June 2019 at our institute. The participants in the study group (n = 42) were injected with platelet-rich plasma at both ends of the tendon graft, while those in the control group (n = 43) received an injection of normal saline. Magnetic resonance imaging signal/noise quotient values of the femoral and tibial ends, knee Lysholm scores, and International Knee Documentation Committee scores were compared at 3, 6, and 12 months postoperatively.

RESULTS

The signal/noise quotient values of the femoral and tibial ends in both groups were higher at 6 months than at 3 and 12 months postoperatively. The signal/noise quotient values of the tibial end were significantly lower in the platelet-rich plasma group than in the normal saline group at all follow-up time points (P < 0.05). The signal/noise quotient values of the tibial and femoral ends in both groups were significantly different at 3, 6, and 12 months postoperatively (P < 0.05). Additionally, the signal/noise quotient values of the tibia were significantly lower than those of the femur in both groups (P < 0.05). The Lysholm and International Knee Documentation Committee scores were significantly better in the platelet-rich plasma group than in the normal saline group only at 3 months postoperatively. No complications, such as knee joint infection or vascular and nerve injuries, occurred in any of the 85 patients. The knee flexion of all patients were more than 90°, and the straight degree was 0°. No joint stiffness was observed in all patients.

CONCLUSION

Platelet-rich plasma can promote tendon-bone healing in grafts and can improve early postoperative knee joint function.

Anterior Cruciate Ligament Reconstruction: Is Biological Augmentation Beneficial?

Surgical reconstruction in anterior cruciate ligament (ACL) ruptures has proven to be a highly effective technique that usually provides satisfactory results. However, despite the majority of patients recovering their function after this procedure, ACL reconstruction (ACLR) is still imperfect. To improve these results, various biological augmentation (BA) techniques have been employed mostly in animal models. They include: (1) growth factors (bone morphogenetic protein, epidermal growth factor, granulocyte colony-stimulating factor, basic fibroblast growth factor, transforming growth factor-β, hepatocyte growth factor, vascular endothelial growth factor, and platelet concentrates such as platelet-rich plasma, fibrin clot, and autologous conditioned serum), (2) mesenchymal stem cells, (3) autologous tissue, (4) various pharmaceuticals (matrix metalloproteinase-inhibitor alpha-2-macroglobulin bisphosphonates), (5) biophysical/environmental methods (hyperbaric oxygen, low-intensity pulsed ultrasound, extracorporeal shockwave therapy), (6) biomaterials (fixation methods, biological coatings, biosynthetic bone substitutes, osteoconductive materials), and (7) gene therapy. All of them have shown good results in experimental studies; however, the clinical studies on BA published so far are highly heterogeneous and have a low degree of evidence. The most widely used technique to date is platelet-rich plasma. My position is that orthopedic surgeons must be very cautious when considering using PRP or other BA methods in ACLR.

Cost-Effectiveness Analysis Based on Intelligent Electronic Medical Arthroscopy for the Treatment of Varus Knee Osteoarthritis

The incidence of inverted knee osteoarthritis is slowly increasing, there are technical limitations in the treatment, and the operation is difficult. In this article, we will study the benefits and costs of arthroscopic cleaning treatments based on intelligent electronic medicine. This article focuses on knee osteoarthritis patients in the EL database. There are 12 male patients, accounting for 66.67%, and 6 female patients, accounting for 33.33%. The average body mass index (BMI) of the patients was 28.08, the average time from first knee discomfort to surgery was 28.44 months, and the average time of arthroscopic debridement treatment for patients with VKOH knee osteoarthritis was 143.11 minutes. One case of perioperative complication occurred within 35 days after operation, which was a soleus muscle intermuscular venous thrombosis. After immobilization and enhanced anticoagulation for 1 week, it was stable without risk of shedding. The average postoperative study time was 20.00 months. The electronic medical arthroscopy cleaning treatment plan in this article can greatly improve the quality of life of patients and can check the pathological state in time, with low cost. In the course of treatment, comprehensive treatment costs can be saved by 45%. Arthroscopic clean-up treatment can not only reduce knee pain and other uncomfortable symptoms, restore normal knee joint function, and improve the quality of life of patients, but also correct the unequal length of the lower limbs, thereby avoiding spinal degeneration caused by knee instability. Therefore, it is the first choice for the treatment of advanced knee osteoarthritis in patients with VKOH.

Bioaugmentation in the surgical treatment of anterior cruciate ligament injuries: A review of current concepts and emerging techniques

Injuries involving the anterior cruciate ligament are among the most common athletic injuries, and are the most common involving the knee. The anterior cruciate ligament is a key translational and rotational stabilizer of the knee joint during pivoting and cutting activities. Traditionally, surgical intervention in the form of anterior cruciate ligament reconstruction has been recommended for those who sustain an anterior cruciate ligament rupture and wish to remain active and return to sport. The intra-articular environment of the anterior cruciate ligament makes achieving successful healing following repair challenging. Historically, results following repair were poor, and anterior cruciate ligament reconstruction emerged as the gold-standard for treatment. While earlier literature reported high rates of return to play, the results of more recent studies with longer follow-up have suggested that anterior cruciate ligament reconstruction may not be as successful as once thought: fewer athletes are able to return to sport at their preinjury level, and many still go on to develop osteoarthritis of the knee at a relatively younger age. The four principles of tissue engineering (cells, growth factors, scaffolds, and mechanical stimuli) combined in various methods of bioaugmentation have been increasingly explored in an effort to improve outcomes following surgical treatment of anterior cruciate ligament injuries. Newer technologies have also led to the re-emergence of anterior cruciate ligament repair as an option for select patients. The different biological challenges associated with anterior cruciate ligament repair and reconstruction each present unique opportunities for targeted bioaugmentation strategies that may eventually lead to better outcomes with better return-to-play rates and fewer revisions.

Biomineralizaion of hydroxyapatite on polyethylene terephthalate artificial ligaments promotes graft-bone healing after anterior cruciate ligament reconstruction: An in vitro and in vivo study

The purpose of the present study is to modify the polyethylene terephthalate ligament with hydroxyapatite via biomineralization and to investigate its effect on graft-bone healing. After biomineralization of hydroxyapatite, the surface characterization of polyethylene terephthalate ligament was examined by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and water contact angle measurements. The compatibility and osteoinduction, along with the underlying signaling pathway involved of hydroxyapatite-polyethylene terephthalate ligament, were evaluated in vitro. Moreover, a rabbit anterior cruciate ligament reconstruction model was established, and the polyethylene terephthalate or hydroxyapatite-polyethylene terephthalate artificial ligament was implanted into the knee. The micro-computed tomography analysis, histological, and immunohistochemical examination as well as biomechanical test were performed to investigate the effect of hydroxyapatite coating in vivo. The results of scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction showed that the hydroxyapatite was successfully deposited on the polyethylene terephthalate ligament. Water contact angle of the hydroxyapatite-polyethylene terephthalate group was significantly smaller than that of the polyethylene terephthalate group. The in vitro study showed that hydroxyapatite coating significantly improved adhesion and proliferation of MC3T3-E1 cells. The osteogenic differentiation of cells was also enhanced through the activation of ERK1/2 pathway. The micro-computed tomography, histological, and immunohistochemical results showed that biomineralization of hydroxyapatite significantly promoted new bone and fibrocartilage tissue formation at 12 weeks postoperatively. Moreover, the failure load and stiffness in the hydroxyapatite-polyethylene terephthalate group were higher than that in the polyethylene terephthalate group. Therefore, biomineralizaion of hydroxyapatite enhances the biocompatibility and osseointegration of the polyethylene terephthalate artificial ligament, thus promoting graft-bone healing for anterior cruciate ligament reconstruction through the activation of ERK1/2 pathway.

Morphological Changes of the Femoral Tunnel and Their Correlation With Hamstring Tendon Autograft Maturation up to 2 Years After Anterior Cruciate Ligament Reconstruction Using Femoral Cortical Suspension

BACKGROUND

Graft healing within the femoral tunnel after anterior cruciate ligament reconstruction (ACLR) using suspensory fixation could be reflected in graft maturation and tunnel morphological changes. However, the correlation between graft maturation and femoral tunnel changes remains unclear.

PURPOSE

To quantitatively evaluate femoral tunnel morphological changes and graft maturation and to analyze their correlation after ACLR using femoral cortical suspension.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Patients who underwent single-bundle ACLR with a hamstring tendon autograft using femoral cortical suspension were included. Preoperative and postoperative (at 6, 12, and 24 months) knee function were evaluated using KT-1000 arthrometer testing, the Lysholm knee scoring scale, and the International Knee Documentation Committee (IKDC) questionnaire. At 1 day, 6 months, 12 months, and 24 months after ACLR, 3-dimensional magnetic resonance imaging was performed to observe the morphology of the femoral tunnel and to evaluate graft maturation using the graft signal/noise quotient (SNQ). The Pearson product moment correlation coefficients (r) of femoral tunnel radii versus clinical outcomes and graft SNQs at last follow-up were analyzed.

RESULTS

A total of 22 patients completed full follow-up. KT-1000 arthrometer, Lysholm, and IKDC scores improved over time postoperatively, but no significant improvement was seen after 12 months (P < .05). The radius of the tunnel containing the graft and the SNQs of the femoral intraosseous graft and intra-articular graft were the highest at 6 months, and they decreased by 24 months but remained higher than their 1-day postoperative values (P < .05). Expansion mainly occurred at the anteroinferior wall of the femoral tunnel. The tunnel aperture radius was positively correlated with SNQs of the intraosseous graft (r = 0.591; P < .05) and intra-articular graft (r = 0.359; P < .05) but not with clinical outcomes.

CONCLUSION

After ACLR using suspensory fixation, morphological changes of the femoral tunnel were mainly observed in the part of the tunnel containing the graft, which expanded at 6 months and reduced by 24 months. Expansion mainly occurred at the anteroinferior wall of the femoral tunnel. Femoral tunnel expansion was correlated with inferior graft maturation but not with clinical outcomes.